2011 was the year of Jessica Chastain. She made a striking debut with "The Tree of Life," followed in rapid succession by "The Help," "The Debt," "Take Shelter" and "Texas Killing Fields." 2011 was also the year Navy SEAL Team Six killed Osama bin Laden in a dangerous and daring anti-terrorism mission. Following its success, it wasn't long before Hollywood was interested turning the events into a film. Fortunately, the project became Kathryn Bigelow's follow-up to her Oscar-winning "The Hurt Locker," and Chastain was tapped for the lead role.

"Zero Dark Thirty" centers on Maya (Chastain), a CIA agent pursuing leads on the ground in Pakistan. Screenwriter Mark Boal compiled 10 years of investigation into two and a half hours of material chronicling the events that led to the historic mission. Even before it has opened in limited release, it has won numerous major critics' awards (including the New York Film Critics and the National Board of Review), four Golden Globe nominations and is a shoo-in for a Best Picture nod when the nominations are announced next month.

Another banner year

The ever-busy Chastain is also having another banner year. Last January, she was nominated for a Best Supporting Actress Oscar for "The Help;" in November, she received strong reviews in "The Heiress" on Broadway; and her role in "Zero Dark Thirty" has already won her more than a half-dozen critics awards, and nominations for Screen Actor Guild and Golden Globe Awards. In the past few weeks, she’s become one of the front-runners for this year’s Best Actress Oscar. And, if that’s not enough, she was picked by Time Magazine as one of "The 100 Most Influential People in the World" in April.

She took the role of Maya when Rooney Mara dropped out of the project. Fortunately, she had just enough time to prepare for it.

"I had three months before we started shooting that I went to school for it, I guess," Chastain said. "I nicknamed Mark ’the professor,’ and I would sit with him and go through the screenplay and ask a lot of questions about the character I was playing and about the CIA. I did some reading. I found two books that were particularly helpful, ’The Looming Tower’ and Michael Scheuer’s book on Osama bin Laden. But, I was never able to meet the real woman it’s based on because she’s an undercover agent. I had to use my imagination to fill in the blanks where the research couldn’t answer the questions."

Couldn’t make it up

The film begins as Maya witnesses an enhanced interrogation in which the suspect is waterboarded. By the end she is dressing down the men in suits who don’t want to risk the resources to follow her leads on the Abottobad compound. Of course we now know Maya was right and that’s where they found bin Laden.

"Yes, there is a very definite arc for Maya," Chastain continued. "But, the wonderful thing about her and actually the most difficult thing about her as an actor to play is she is someone who does not explain her subtext. She doesn’t take the time to say how she feels. She doesn’t sit down and have a drink with someone and talk about her feelings. She’s so haunted by this mission.

"A lot of the arc had to almost be mapped out before we even started shooting, so much so that I found chapters in the script that were marked by different markers for her when something might change. Is she brushing her hair? What kind of effort does she put into herself when we see her? So we understand something about her before she even opens her mouth. So much of Maya is told without her explaining it. It has to be seen in her appearance and in her eyes and how she’s relating to the other characters, and because of that, for me, it’s more difficult than a character like Celia Foote [in ’The Help’] where you work on the voice, you change your body, you show up and you do a scene ten different ways, and you get to be open and big, and then just throw it to the wall and see what sticks. This is something you have to know what you’re doing before you show up. You can’t just make it up."

Keeping a secret

"Zero Dark Thirty" was a top-secret movie project because the subject matter alone made it a highly anticipated film, and its real world context would open it up for much scrutiny. Perhaps the hardest aspect of the role for Chastain was keeping the experience to herself.

"I am the worst at keeping secrets," Chastain admitted. "I am the kind of person that the second I buy someone a Christmas present, I tell them what I bought them. I don’t wait until Christmas. I’m not good at it. So when I was cast in this, I was so excited about this character of Maya. I found her to be really inspiring and the script was incredible. It was so eye opening, but I had to keep it a secret and there was a lot of press coming out and people were speculating that I was a Navy SEAL wife and all this stuff.

"I had to just really hold my tongue for a year. So I’m very excited that people are now seeing the film and they’re realizing it’s not a propaganda film and it doesn’t have an agenda. It just tries to show this moment in history as accurately as possible."

Compassion for her character

Many of the film’s Middle Eastern sequences were filmed in Jordan, doubling for Pakistan. Even in Jordan, Chastain had moments where she was reminded of the region’s gender inequality.

"We went to a hotel restaurant in Amman, which is a pretty liberal city I think, and the waiter wouldn’t give me a menu," Chastain recalled. "He gave the men menus at the table, so Jason [Clarke] ordered for me that day. For me, it’s difficult being in that kind of a situation. I felt invisible as a woman. I don’t like that. Any time anything like that happened, it was just another log to the Maya ’fire,’ of her feeling invisible, like no one would listen to her or talk to her."

In the end, Chastain expressed her thanks for women like Maya and her entire team that worked for 10 years to find bin Laden, and continue to work preventing the next terrorist attack.

"In playing the character I just had so much compassion for this woman who really sacrificed so much for this mission," Chastain said. "In our film, she becomes a stranger to herself at the end of the film. I just loved her from the moment I read her, what Mark created. He took the dry facts of this manhunt, the greatest manhunt in history, and what he was able to do with the dry facts was to create this amazing arc and really put the light on the people who worked so hard that never get the acknowledgement for that. So I have an enormous amount of compassion for everything they dealt with."

No spoilers

The story of SEAL Team Six is so compelling that there was more than one movie made about them. Another film directed by John Stockwell was released on VOD in November. Bigelow’s film attempts to reveal the drama in a story whose ending we already know.

"Well, certainly it doesn’t lend itself to spoilers," Bigelow said. "I think what was so strong and what struck me so much about the screenplay was how inherently dramatic the story is and was and that ten year journey was. It was a very riveting, galvanizing story that gave us a real glimpse into the intelligence hunt on the ground through the eyes of the characters that Jessica and Jason play of what it would be like to hunt the world’s most dangerous man, the dedication, the courage, the sacrifice and the price that they paid both personally and then some of their colleagues who did not survive. It was inherently a very dramatic piece. The fact that you knew the ending only amplified the drama."

Not about gender

With "The Hurt Locker," Bigelow set a record as the first woman to win a Best Director Oscar. She would seem a good fit, then, to tell the story of a female CIA agent responsible for locating the world’s most wanted man. Bigelow did not want to make "Zero Dark Thirty" about gender.

"I have to say that if that character at the center of that hunt had been a man, I would have been very happy and eager to engage in that story as well," Bigelow said. "I think what was important to me was that this was a very strong character at the center of this hunt and that the movie doesn’t engage necessarily in gender politics about that character.

"She is not defined by a man. She is not defined by a love interest. She is defined by her actions. I think that’s a character that’s very inspiring and is beautifully played by Jessica. So it was exciting to me. I will say that I was surprised and excited that it was a woman. I was thrilled that it was a woman and to find out that there were women at the center of this hunt, but there were also a lot of men who worked very, very hard as well. It was a very wonderful screenplay so I was very happy."